Hydrofluoropolyether-based azeotropic or near azeotropic compositions

ABSTRACT

Azeotropic or near azeotropic compositions based on difluoromethoxy-bis(difluoromethyl ether) and/or 1-difluoromethoxy-1,1,2,2-tetrafluoroethyl difluoromethyl ether.

The present invention relates to azeotropic or near azeotropiccompositions based on hydrofluoropolyethers (HFPE) to be used assubstitutes of 1,1,2-trichloro-1,2,2-trifluoroethane (CFC 113) as asolvent.

More specifically the present invention relates to azeotropic or nearazeotropic mixtures characterized by ODP (ozone Depletion Potential)values equal to zero or lower than 0.02, by low GWP (Global WarmingPotential) and VOC (Volatile Organic Compounds) values to be used asdetergents, i.e. as solvent for cleaning and drying agents insubstitution of CFC 113.

As it is known, CFC 113 has been widely used as solvent and/or dryingagent for industrial applications requiring the removal of organicsubstances (greases, waxes, oils, resins) and/or water from solidsurfaces of various nature (metal, glass, plastics or compositessurfaces).

For example, CFC 113 has been commonly used for the degreasing andremoval of abrasives from metal surfaces of mechanical parts havingcomplex shapes, for the cleaning of high quality and high precisionmetallic components for which an accurate surface cleaning is requiredand for the removal of water traces from valuable articles and from highquality components previously subjected to washing with aqueous mediums.

Specifically in the electronic field CFC 113 has been used for theremoval of organic products and moisture traces present on the surfaceof molded circuits characterized by an high density of hardly washablecomponents and for which an high reliability is required.

Contaminant removal processes from solid surfaces (metals, plasticmaterials, glass) are carried out by methods implying the solvent actionin liquid phase (cold or hot) and/or by vapour action; in the lattercase the article is exposed to the fluid vapours at its boilingtemperatures. Vapours, by condensing on the article cold surface performthe solvent and cleaning action.

In these applications CFC 113 has often been used also in combinationwith organic solvents, in particular as azeotropic or near azeotropicmixtures in order to substantially have the same composition in thevapour and in the liquid phase and to avoid fractionations during theapplication phases in industrial cleaning processes, during thehandling, distillation and recovery steps of the exhausted solvent.

CFC 113 is characterized by particular chemical-physical properties suchas to be advantageously used in the previously described field andallows, furthermore, a simple, cheap and safe use since it is stable,non flammable and non toxic.

CFCs and specifically CFC 113 have, however, the drawback to involve anhigh destroying power on the stratospheric ozone layer, wherefore, theproduction and commercialization have been subjected to regulations andthen banned since Jan. 1, 1995.

The need was felt to identify substitutes able to replace CFC 113 in thementioned use fields while respecting and protecting the environment.

To this purpose, in the solvency field, the use of alternative systemsbased on aqueous solutions, of non halogenated organic solvents and ofhydrohalogenated solvents of HCFC type has been proposed.

The alternatives using the aqueous system imply however variousinconveniences.

In particular it happens that articles with microhollow, capillary holesand surface irregularities, are insufficiently washed due to therelatively high water surface pressure, also in the presence ofsurfactants.

The water removal rate is very low and if this is not completelyremoved, it can be the cause of corrosion phenomena of the metalarticles previously subjected to washing. Therefore such surfaces mustbe suitably dried after they have been cleansed.

Hydrocarbons, alcohols or other non halogenated organic solvents, due totheir high flammability, have not a generalized use and require in anycase great investments in order to avoid fire and explosion risks in theplants using them.

Furthermore, these solvents represent an atmospheric pollution source,since, if exposed to the sun light in the presence of nitrogen oxides,undergo oxidative degradation phenomena, with the formation of the socalled ozone-rich oxidizing smog. For this negative characteristic theseproducts are classified as VOC (Volatile Organic Compound) compounds.

The hydrohalogenated solvents represent a class of products more similarto CFC 113, they give lower use complications and allow more generalizedapplications in comparison with the above mentioned alternative systems.

HCFC 141b, which is one of the most valid substitutes for theseapplications, has however the disadvantage to be moderately flammableand especially to be characterized by an ODP value equal to 0.11 (CFC 11has ODP=l) and therefore it has been subjected to limitations.

The use of non toxic solvents having a low environmental impact,constituted by hydrofluoropolyethers and compositions thereof havinglimited concentrations of polar substances selected from alcohols,ketones and ethers as described in the European patent application EP805,199 is known in the field of oil, grease, wax etc., removal fromsurfaces.

In said application no reference is made to mixtures having azeotropicor near azeotropic behaviour to be used in the industrial solvencyfield.

In connection with what described in the prior art the need was felt tohave available substitutes to CFC 113.

It was indeed necessary to have available products able to remove oilysubstances similarly to CFC 113, i.e. by partial or total solubilizationof the substances to be removed, therefore differently from pure oradditivated hydrofluoropolyethers, in order to guarantee a more accurateand quicker cleaning of articles having complex shapes and microhollows,with remarkable advantages in efficiency and economic saving terms ofthe same cleaning operation.

Preferably the substitutes of CFC 113 should be drop-in, i.e. thesubstitutes should be used in the existing plants without involvingsubstantial modifications and allow to maintain practically unchangedthe various operating steps of the article cleaning process.

Finally, the need was evident to limit or eliminate the environmentaland safety problems typical of the conventional solvents (hydrocarbons,HCFC), and to reduce the cleaning operation costs deriving from the pureor only addivitated HFPE use, since, as known, these products areobtained by complex and expensive processes.

The Applicant has surprisingly and unexpectedly found that assubstitutes of CFC 113 hydrofluoropolyether-based (HFPE) mixtures,object of the present invention, have azeotropic or near azeotropicbehaviour, they are drop-in of CFC 113, have an environmental impactexpressed in ODP terms equal to zero or <0.02 and low GWP and VOCvalues.

It is therefore an object of the present invention azeotropic or nearazeotropic compositions, based on difluoromethoxy-bis(difluoromethylether) (HFPE1) and on 1-difluoromethoxy-1,1,2,2-tetrafluoroethyl (AF9925/031.EST) difluoromethyl ether (HFPE2), to be used as substitutes ofCFC 113, consisting essentially of:

composition % by weight general preferred I) difluoromethoxy  2-60  2-54bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);1,1-dichloro-2,2,2-trifluoroethane 98-40 98-46 (CHCl₂CF₃, HCFC 123) II)difluoromethoxy  1-95 25-95 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);n-pentane 99-5  75-5  III) difluoromethoxy  1-99 25-98bis(difluoromethyl ether) (HFC₂OCF₂OCF₂H); iso-pentane 99-1  75-2  IV)difluoromethoxy  1-60 20-60 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);dimethyl ketone (acetone) 99-40 80-40 V) difluoromethoxy  1-99 10-98bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); 1,1,1,3,3-pentafluorobutane99-1  90-2  (CF₃CH₂CF₂CH₃, HFC 365 mfc) VI) difluoromethoxy  1-40 10-40bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); 1,1,1,4,4,4-hexafluorobutane99-60 90-60 (CF₃CH₂CH₂CF₃, HFC 356 ffa) VII) difluorometoxy  1-96 25-96bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); methoxymethyl methylether99-14 75-14 VIII) difluoromethoxy 30-99 35-98 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂); n-hexane 70-1  65-2  IX) difluoromethoxy  1-99 18-95bis(difluoromethyl ether) (HCF₂OCF₂OCF₂); trans 1,2-dichloroethylene99-1  82-5  (ClCHCHCl, tDCE) X) 1-difluoromethoxy  1-93 25-931,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H);n-pentane 99-7  75-7  XI) 1-difluoromethoxy 30-99 50-981,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H);dimethyl ketone (acetone) 70-1  50-2  XII) 1-difluoromethoxy 50-99 60-981,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); methylalcohol 50-1  40-2  XIII) 1-difluoromethoxy 15-99 25-98 1,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); n-hexane85-1  75-2  XIV) 1-difluoromethoxy  1-99 15-95 1,1,2,2-tetrafluoroethyldifluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); trans 1,2-dichloroethylene99-1  85-5  (ClCHCHCl) XV) 1-difluoromethoxy  5-99 10-981,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); ethylalcohol 95-1  90-2 

More specifically the azeotropic compositions, i.e. showing an absoluteminimum or maximum in the boiling temperature at the pressure of 1.013bar with respect to the pure products is noticed, are defined asfollows:

Compositions are defined within +/− 2% by weight A)difluoromethoxy-bis(difluoromethyl ether) 24% by wt. (HCF₂OCF₂OCF₂H);1,1-dichloro-2,2,2-trifluoroethane 76% by wt. (CHCl₂CF₃, HCFC 123) B)difluoromethoxy-bis(difluoromethyl ether) 62% by wt. (HCF₂OCF₂OCF₂H);n-pentane 38% by wt. C) difluoromethoxy-bis(difluoromethyl ether) 63% bywt. (HCF₂OCF₂OCF₂H); iso-pentane 36% by wt. D)difluoromethoxy-bis(difluoromethyl ether) 42% by wt. (HCF₂OCF₂OCF₂H);dimethyl ketone (acetone) 58% by wt. E)difluoromethoxy-bis(difluoromethyl ether) 60% by wt. (HCF₂OCF₂OCF₂H);1,1,1,3,3-pentafluorobutane 40% by wt. (CF₃CH₂CF₂CH₃, HFC 365 mfc) F)difluoromethoxy-bis(difluoromethyl ether) 20% by wt. (HCF₂OCF₂OCF₂H);1,1,1,4,4,4-hexafluorobutane 80% by wt. (CF₃CH₂CH₂CF₃, HFC 356 ffa) C)difluoromethoxy-bis(difluoromethyl ether) 59% by wt. (HCF₂OCF₂OCF₂H);methoxymethyl methyl ether 41% by wt. H)difluoromethoxy-bis(difluoromethyl ether) 75% by wt. (HCF₂OCF₂OCF₂H);n-hexane 25% by wt. I) difluoromethoxy-bis(difluoromethyl ether) 75% bywt. (HCF₂OCF₂OCF₂H); trans 1,2-dichloroethylene 25% by wt. (ClCHCHCl,tDCE) L) 1-difluoromethoxy-1,1,2,2-tetrafluoroethyl 61% by wt.difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); n-pentane 39% by wt. M)1-difluoromethoxy-1,1,2,2-tetrafluoroethyl 79% by wt. difluoromethylether (HCF₂OCF₂CF₂OCF₂H); dimethyl ketone (acetone) 21% by wt. N)1-difluoromethoxy-1,1,2,2-tetrafluoroethyl 94% by wt. difluoromethylether (HCF₂OCF₂CF₂OCF₂H); methyl alcohol  6% by wt. Q)1-difluoromethoxy-1,1,2,2-tetrafluoroethyl 74% by wt. difluoromethylether (HCF₂OCF₂CF₂OCF₂H); n-hexane 26% by wt. P)1-difluoromethoxy-1,1,2,2-tetrafluoroethyl 50% by wt. difluoromethylether (HCF₂OCF₂CF₂OCF₂H); trans 1,2-dichloroethylene 50% by wt.(ClCHCHCl, tDCE) Q) 1-difluoromethoxy-1,1,2,2-tetrafluoroethyl 95% bywt. difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); ethyl alcohol  5% by wt.

The azeotropic or near azeotropic mixtures, object of the presentinvention, are based on two hydrofluoropolyethers: HFPE1 and HFPE2,obtained by alkaline salt decarboxylation processes obtained byhydrolysis and salification of the corresponding acylfluorides, usingprocesses known in the art. For example, decarboxylation is carried outin the presence of hydrogen-donor compounds, for example water, attemperatures of 140-170° C. and under a pressure of at least 4 atm. Seefor example EP 695,775 and the examples reported therein; this patent isherein incorporated by reference.

The main features of the two hydrofluoropolyethers of the azeotropic ornear azeotropic mixtures, are reported in Table 1 in comparison with CFC113.

The fluids in Table I are characterized by a combination ofchemical-physical properties such as chemical inertia, high thermalstability, non flammability, evaporation heat and boiling temperaturesuch as to be particularly suitable, in admixture with other organicsolvents as defined above, for the CFC 113 substitution in the abovementioned industrial applications.

Preliminary studies relating to acute toxicity show that the productshave a low biologic activity.

The Applicant has found that the particular distribution of the hydrogenatoms on the terminal ends and the presence of an ethereal bond preventsdehydrofluorination reactions, which lead to the formation ofpotentially toxic olefins and avoids the acidity formation whichinvolves metal material corrosion phenomena.

The HFPEs of the invention have an ODP value equal to zero and a lowGWP.

The HFPE-based mixtures offer an advantageous combination of the boilingtemperature and evaporation heat such as to give them adetergency/drying time suitably short and fit to the continuousoperations, both in liquid and in vapour phase.

The evaporation heat is sufficiently low and such as not to allow thesolidification of the water trace which must be removed.

In the detergency, solvency and drying applications, the use of mixtureshaving an azeotropic or near azeotropic behaviour is essential, in orderto avoid segregations or meaningful variations of the fluid compositionduring the industrial processes phases involving phase change phenomena(evaporation and condensation), as in the solvency case, and, moregenerally, during all the fluid handling and storage operations in whichaccidental leaks can take place due to liquid evaporation andconsequently variations of the composition of the fluid.

The composition variations which take place in all the cases wherein nonazeotropic mixtures are used, involve deviations of the solvent agentperformances and the need to make appropriated refillings in order torestore the original composition and therefore the mixturechemical-physical characteristics.

Furthermore, when the non azeotropic or non near-azeotropic compositionscontain more volatile flammable components, the vapour phase becomesrich in such component until reaching the flammability limit, withevident risks for the use safety. Likewise, when the flammable componentis less volatile, it concentrates in the liquid phase giving rise to aflammable liquid.

Mixtures having azeotropic or near azeotropic behaviour avoid the abovedisadvantage even when a flammable compound is present

An azeotrope is a particular composition which has singularchemical-physical, unexpected and unforeseeable properties of which themost important ones are reported hereinafter.

An azeotrope is a mixture of two or more fluids which has the samecomposition in the vapour phase and in the liquid one when it is inequilibrium under determined conditions.

The azeotropic composition is defined by particular temperature andpressure values; in these conditions the mixtures undergo phase changesat constant composition and temperature as pure compounds.

A near azeotrope is a mixture of two or more fluids which has a vapourcomposition substantially equal to that of the liquid and undergo phasepassages without substantially modifying the composition andtemperature. A composition is near azeotropic when, after evaporation ata constant temperature of 50% of the liquid initial mass, the per centvariation of the vapour pressure between the initial and finalcomposition results lower than 10%; in the case of an azeotrope, novariation of the vapour pressure between the initial composition and theone obtained after the 50% liquid evaporation is noticed.

Azeotropic or near azeotropic mixtures belong to the cases showingmeaningful, both positive and negative, deviations from the Raoult law.As known to the skilled in the art, such law is valid for ideal systems.

When such deviations are sufficiently marked, the mixture vapourpressure in the azeotropic point must be therefore characterized byvalues either higher or lower than those of the pure compounds.

It is evident that, if the mixture vapour pressure curve shows amaximum, this corresponds to a minimum of boiling temperature; viceversato a vapour pressure minimum value, a maximum of boiling temperaturecorresponds.

The azeotropic mixture has only one composition for each temperature andpressure value.

However, by changing temperature and pressure, more azeotropiccompositions starting from the same components can be obtained.

For example, the combination of all the compositions of the samecomponents which have a minimum or a maximum in the boiling temperatureat different pressure levels form an azeotropic composition field.

It has been found that the near azeotropic compositions of points I,III, IV, V, VI, VII remain near azeotropic also when a portion ofdifluoromethoxy-bis(difluoromethyl ether) is substituted with1-difluoromethoxy-1,1,2,2-tetrafluoroethyldifluoromethyl ether up to 40%by weight.

The same for compositions of points XI, XII and XV when a portion of1-difluoromethoxy-1,1-2,2-tetrafluoroethyl difluoromethyl ether issubstituted by difluoromethoxy-bis(difluoromethyl ether), up to 40% byweight.

The same for compositions of points II, VIII and IX wherein a part ofdifluoromethoxy-bis(difluoromethyl ether) is replaced by1-difluoromethoxy-1,1,2,2-tetrafluoroethyldifluoromethyl ether up to 50%by weight.

Likewise for the compositions of points X, XIII and XIV wherein aportion of 1-difluoromethoxy-1,1,2,2-tetrafluoroethyl difluoromethylether is replaced by difluoromethoxy-bis(difluoromethyl ether) up to 50%by weight.

Another object of the present invention are ternary near azeotropiccompositions based on difluoromethoxy-bis(difluoromethyl ether) andhydrocarbons consisting essentially of:

% by weight XVI) difluoromethoxy-bis(difluoromethyl ether)  1-42(HCF₂OCF₂OCF₂H); 1,1-dichoro-2,2,2-trifluoroethane 98-24 (CHCl₂CF₃, HCFC123) hydrocarbon  1-35 XVII) difluoromethoxy-bis(difluoromethyl ether) 1-64 (HCF₂OCF₂OCF₂H); 1,1,1,3,3-pentafluorobutane 98-1  (CF₃CH₂CF₂CH₃,HFC 365 mfc) hydrocarbon  1-35 XVIII) difluoromethoxy-bis(difluoromethylether)  1-22 (HCF₂OCF₂OCF₂H); 1,1,1,4,4,4-hexafluorobutane 98-43(CF₃CH₂CH₂CF₃, HFC 356 ffa) hydrocarbon  1-35

Among hydrocarbons, n-pentane and iso-pentane are preferred, preferablyin the range 1-20% by weight.

Likewise, an object of the present invention are ternary near azeotropiccompositions based on difluoromethoxy-bis(difluoromethyl ether) andalcohols essentially consisting of:

% by weight XIX) difluoromethoxy-bis(difluoromethyl ether)  1-55(HCF₂OCF₂OCF₂H) 1,1-dichloro-2,2,2-trifluoroethane 98-35 (CHCl₂CF₃, HCFC123) alcohol  1-10 XX) difluoromethoxy-bis(difluoromethyl ether)  1-89(HCF₂OCF₂OCF₂H); 1,1,1,3,3-pentafluorobutane 98-1  (CF₃CH₂CF₂CH₃, HFC365 mfc) alcohol  1-10 XXI) difluoromethoxy-bis(difluoromethyl ether) 1-35 (HCF₂OCF₂OCF₂H); 1,1,1,4,4,4-hexafluorobutane 98-55 (CF₃CH₂CH₂CF₃,HFC 356 ffa) alcohol  1-10

Preferred alcohol is methyl alcohol; preferably between 1 and 5% byweight.

A further object of the present invention are azeotropic or nearazeotropic compositions, as described at points from I) to XXI) and fromA) to Q), wherein, a portion of HFPE1 and/or HFPE2 is replaced by ahydrofluoropolyethers having the same structure of HFPE1 or HFPE2 buthaving boiling point in the range of 5-80° C. In this case, one canspeak of fluids consisting essentially of HFPE1 and/or HFPE2.

In the detergency applications the mentioned mixtures can be used incombination with stabilizing agents in order to limit the radicalicdecomposition reactions which, as known, are favoured by the temperatureand the metal presence. The degradation reactions especially concerningthe mixtures containing HCFC 123, HFC 356 ffa and 365 mfc, can always beprevented or reduced by the use of nitroparaffins and/or organicsubstances in the molecule of which conjugated double bonds are present.

The stabilizing agents are generally used in amounts of 0.1-5% byweight.

To the compositions of the invention, non ionic surfactant agentssoluble therein can be added to decrease the interfacial tension withwater and favour the water removal from the surfaces subjected todrying. The used surfactant concentration is in the range 0.005%-5% byweight on the azeotropic or near azeotropic components, i.e. on thesolvent/drying agent.

The compositions of the present invention can be used also in aerosolapplications for the electronic components cleaning in combination withone or more propellants, preferably selected from HFC 134a(1,1,1,2-tetrafluoroethane), HFC 227ea(1,1,1,2,3,3,3-heptafluoropropane) or mixtures thereof.

EXAMPLE 1

The evaluation of the azeotropic or near azeotropic behaviour is made asfollows: the mixture of known composition and weight is introduced in asmall glass cell, previously evacuated, having an internal volume equalto about 20 cm³, equipped with metal connections, feeding valve and apressure transducer to evaluate the system vapour pressure.

The filling volumetric ratio is initially equal to about 0.8%v.

The cell is introduced in a thermostatic bath and the temperature isslowly changed until obtaining a vapour pressure equilibrium value equalto 1.013 bar. The corresponding temperature is recorded and itrepresents the mixture boiling temperature at the 1.013 bar pressure.

The temperature is measured close to the equilibrium cell with athermometer the accuracy of which is equal to ±0.01° C.; particularattention was paid so that the external temperature measured in the bathis really the internal one of the cell.

By changing the mixture composition it is possible to estimate possibledeviations with respect to the ideality and therefore to identify theazeotropic composition which, as said, will be characterized by anabsolute minimum or maximum with respect to the pure components.

In order to confirm the azeotropic or near azeotropic behaviour, themixture characterized by a minumum or a maximum of the boilingtemperature and others identified close to the azeotrope were subjectedto evaporation test at the azeotrope constant temperature.

The cell content is removed at constant temperature by evaporation untilhaving a loss corresponding to 50% by weight of the initial amount.

From the evaluation of the initial and final pressure the per centvariation of the vapour pressure is calculated: if the decrease is equalto zero the mixture in those conditions is an azeotrope, if the decreaseis <10% its behaviour is of a near azotrope.

It is known that a near azetropic mixture has a behaviour closer andcloser to a true azeotrope if the per cent variation is lower and lowerand near to zero.

As a further confirmation of the azeotropic and near azeotropicbehaviour, togheter with the above reported evaluations, analyses of thecomposition of some mixtures object of the present invention, have beencarried out by gaschromatographic method before and after theevaporation test.

The azeotropic mixtures maintain unchanged, within the limits of theerror of the analytical methods, the composition after the liquidevaporation, while in the case of near azeotropic systems, limitedvariations of composition are observed.

In all the measurements reported in Tables from 2 to 18 the visualobservation of the liquid phase at its normal boiling temperature has inany case shown that no phase separations took place and that thesolutions were limpid and homogeneous.

TABLE 1 Hydrofluoropolyether chemical-physical and toxicologicalcharacteristics CFC 113 1,1,2-tri- chloro 1,2,2-tri- ChemicalHCF₂OCF₂OCF₂H HCF₂OCF₂CF₂OCF₂H fluro- structure (HFPE1) (HFPE2) roethaneMolecular mass 184.04 234.05 187.38 Boiling 35.39 58.21 47.55temperature (° C., at 1.013 bar) Evaporation 165 139 144 latent heat(KJ/Kg, at 1.013 bar) Liquid density 1.54 1.60 1.56 at 25° C. (g/cm³)Flammability non flammable non flammable non in air flammable (% volume)ODP CFC 0 0 1.07 11 = 1 lifetime <10 <10 110 (years) Acutetoxicity >5000 >5000 43000 in rats per os, LD₅₀ (ppmv/4 hours) Acutetoxicity >32000 >32000 50000 in rats by inhalation, LC₅₀ (ppmv/4 hours)Surface 14.0 15.5 18.1 pressure at 20° C. (dynes/cm) Isotherm 1.5 0.6 1evaporation speed at 20° C. (mg/min)

TABLE No 2 boiling temperature evaluation at the pressure of 1.013 barHCF₂OCF₂OCF₂H/HCFC 123 binary mixture COMPOSITION BOILING TEMPERATUREHCF₂OCF₂OCF₂H (% by wt.) (° C.) 0 27.54 5.4 27.00 7.7 26.77 13.0 26.7516.3 26.71 20.1 26.70 24.2 26.68 26.1 26.71 40.0 26.96 49.3 27.21 60.227.86 72.6 29.39 100 35.39

TABLE No 2 boiling temperature evaluation at the pressure of 1.013 barHCF₂OCF₂OCF₂H/HCFC 123 binary mixture COMPOSITION BOILING TEMPERATUREHCF₂OCF₂OCF₂H (% by wt.) (° C.) 0 27.54 5.4 27.00 7.7 26.77 13.0 26.7516.3 26.71 20.1 26.70 24.2 26.68 26.1 26.71 40.0 26.96 49.3 27.21 60.227.86 72.6 29.39 100 35.39

TABLE 3 boiling temperature evaluation at the pressure of 1.013 barHCF₂OCF₂OCF₂H/n-pentane binary mixture COMPOSITION BOILING TEMPERATUREHCF₂OCF₂OCF₂H (% by weight) (° C.) 0 35.79 12.6 26.42 25.9 23.00 50.021.45 61.9 21.32 74.9 21.35 83.4 21.49 87.0 21.70 95.6 25.18 100 35.39

TABLE 3 boiling temperature evaluation at the pressure of 1.013 barHCF₂OCF₂OCF₂H/n-pentane binary mixture COMPOSITION BOILING TEMPERATUREHCF₂OCF₂OCF₂H (% by weight) (° C.) 0 35.79 12.6 26.42 25.9 23.00 50.021.45 61.9 21.32 74.9 21.35 83.4 21.49 87.0 21.70 95.6 25.18 100 35.39

TABLE 4 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂OCF₂H/iso-pentane binary mixture COMPOSITION BOILINGTEMPERATURE HCF₂OCF₂OCF₂H (% by wt.) (° C.) 0 27.18 14.2 21.02 20.420.00 39.5 17.70 61.0 17.40 63.1 17.35 80.1 17.68 90.4 19.80 100 35.39

TABLE 4 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂OCF₂H/iso-pentane binary mixture COMPOSITION BOILINGTEMPERATURE HCF₂OCF₂OCF₂H (% by wt.) (° C.) 0 27.18 14.2 21.02 20.420.00 39.5 17.70 61.0 17.40 63.1 17.35 80.1 17.68 90.4 19.80 100 35.39

TABLE 5 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂OCF₂H/acetone binary mixture COMPOSITION HCF₂OCF₂OCF₂HBOILING TEMPERATURE (% by wt.) (° C.) 0 56.50 28.1 57.88 41.7 58.11 51.057.98 61.2 56.63 74.8 53.62 100 35.39

TABLE 5 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂OCF₂H/acetone binary mixture COMPOSITION HCF₂OCF₂OCF₂HBOILING TEMPERATURE (% by wt.) (° C.) 0 56.50 28.1 57.88 41.7 58.11 51.057.98 61.2 56.63 74.8 53.62 100 35.39

TABLE 6 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂OCF₂H/HFC 365 mfc binary mixture COMPOSITION BOILINGTEMPERATURE HCF₂OCF₂OCF₂H (% by wt.) (° C.) 0 40.09 10.0 36.89 20.034.92 30.0 33.71 40.1 33.01 50.1 32.66 60.1 32.60 75.0 33.13 80.0 33.54100 35.39

TABLE 6 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂OCF₂H/HFC 365 mfc binary mixture COMPOSITION BOILINGTEMPERATURE HCF₂OCF₂OCF₂H (% by wt.) (° C.) 0 40.09 10.0 36.89 20.034.92 30.0 33.71 40.1 33.01 50.1 32.66 60.1 32.60 75.0 33.13 80.0 33.54100 35.39

TABLE 7 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂OCF₂H/HFC 356 ffa binary mixture COMPOSITION BOILINGTEMPERATURE HCF₂OCF₂OCF₂H (% by wt.) (° C.) 0 24.71 10.1 24.16 19.924.05 29.9 24.22 40.0 24.65 49.9 25.29 60.1 26.24 70.1 27.60 80.1 29.65100 35.39

TABLE 7 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂OCF₂H/HFC 356 ffa binary mixture COMPOSITION BOILINGTEMPERATURE HCF₂OCF₂OCF₂H (% by wt.) (° C.) 0 24.71 10.1 24.16 19.924.05 29.9 24.22 40.0 24.65 49.9 25.29 60.1 26.24 70.1 27.60 80.1 29.65100 35.39

TABLE 8 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂OCF₂H/metoxymethyl methyl ether binary mixture COMPOSITIONHCF₂OCF₂OCF₂H (% by wt.) BOILING TEMPERATURE, ° C. 0 41.96 20.1 42.8027.5 43.05 38.1 43.40 50.6 43.78 59.1 43.74 60.2 43.76 65.0 43.53 72.142.95 78.7 41.66 100 35.39

TABLE 8 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂OCF₂H/metoxymethyl methyl ether binary mixture COMPOSITIONHCF₂OCF₂OCF₂H (% by wt.) BOILING TEMPERATURE, ° C. 0 41.96 20.1 42.8027.5 43.05 38.1 43.40 50.6 43.78 59.1 43.74 60.2 43.76 65.0 43.53 72.142.95 78.7 41.66 100 35.39

TABLE 9 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂OCF₂H/n-hexane binary mixture COMPOSITION BOILINGTEMPERATURE HCF₂OCF₂OCF₂H (% by wt.) (° C.) 0 68.00 15.4 43.86 34.035.15 50.8 33.12 65.6 32.42 74.7 32.10 78.1 32.15 90.1 32.22 100 35.39

TABLE 9 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂OCF₂H/n-hexane binary mixture COMPOSITION BOILINGTEMPERATURE HCF₂OCF₂OCF₂H (% by wt.) (° C.) 0 68.00 15.4 43.86 34.035.15 50.8 33.12 65.6 32.42 74.7 32.10 78.1 32.15 90.1 32.22 100 35.39

TABLE 10 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂OCF₂H/ tDCE binary mixture COMPOSITION BOILING TEMPERATUREHCF₂OCF₂OCF₂H (% by wt.) (° C.) 0 46.70 6.0 40.65 6.7 40.05 24.2 33.0240.5 30.96 59.1 29.85 70.2 29.79 75.1 29.76 84.8 30.13 94.2 31.88 10035.39

TABLE 10 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂OCF₂H/ tDCE binary mixture COMPOSITION BOILING TEMPERATUREHCF₂OCF₂OCF₂H (% by wt.) (° C.) 0 46.70 6.0 40.65 6.7 40.05 24.2 33.0240.5 30.96 59.1 29.85 70.2 29.79 75.1 29.76 84.8 30.13 94.2 31.88 10035.39

TABLE 11 evaluation of the boling temperature at the pressure of 1.013bar HCF₂OCF₂CF₂OCF₂H/n-pentane binary mixture COMPOSITION BOILINGTEMPERATURE HCF₂OCF₂CF₂OCF₂H (% by wt.) (° C.) 0 35.79 17.3 31.75 29.131.52 60.8 31.2 68.0 31.04 72.1 31.08 74.3 31.15 79.3 31.25 84.3 31.7793.4 35.83 100 58.21

TABLE 11 evaluation of the boling temperature at the pressure of 1.013bar HCF₂OCF₂CF₂OCF₂H/n-pentane binary mixture COMPOSITION BOILINGTEMPERATURE HCF₂OCF₂CF₂OCF₂H (% by wt.) (° C.) 0 35.79 17.3 31.75 29.131.52 60.8 31.2 68.0 31.04 72.1 31.08 74.3 31.15 79.3 31.25 84.3 31.7793.4 35.83 100 58.21

TABLE 12 boiling temperature evaluation at the pressure of 1.013 barHCF₂OCF₂CF₂OCF₂H/acetone binary mixture COMPOSITION BOILING TEMPERATUREHCF₂OCF₂CF₂OCF₂H (% by wt.) (° C.) 0 56.50 15.5 56.83 30.8 58.23 40.759.45 58.6 62.87 70.0 65.04 79.4 65.96 85.5 65.28 89.9 64.41 100 58.21

TABLE 12 boiling temperature evaluation at the pressure of 1.013 barHCF₂OCF₂CF₂OCF₂H/acetone binary mixture COMPOSITION BOILING TEMPERATUREHCF₂OCF₂CF₂OCF₂H (% by wt.) (° C.) 0 56.50 15.5 56.83 30.8 58.23 40.759.45 58.6 62.87 70.0 65.04 79.4 65.96 85.5 65.28 89.9 64.41 100 58.21

TABLE 13 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂CF₂OCF₂H/methyl alcohol binary mixture COMPOSITION BOILINGTEMPERATURE HCF₂OCF₂CF₂OCF₂H (% by wt.) (° C.) 0 65.00 21.0 63.15 40.359.95 50.0 57.88 73.8 53.45 84.3 52.18 88.7 51.83 93.9 51.38 96.5 53.87100 58.21

TABLE 13 evaluation of the boiling temperature at the pressure of 1.013bar HCF₂OCF₂CF₂OCF₂H/methyl alcohol binary mixture COMPOSITION BOILINGTEMPERATURE HCF₂OCF₂CF₂OCF₂H (% by wt.) (° C.) 0 65.00 21.0 63.15 40.359.95 50.0 57.88 73.8 53.45 84.3 52.18 88.7 51.83 93.9 51.38 96.5 53.87100 58.21

TABLE 14 boiling temperature evaluation at the pressure of 1.013 barHCF₂OCF₂CF₂OCF₂H/n-hexane binary mixture COMPOSITION BOILING TEMPERATUREHCF₂OCF₂CF₂OCF₂H (% by wt.) (° C.) 0 68.00 20.6 56.24 39.7 48 81 59.946.74 73.8 46.66 78.7 46.76 89.9 49.00 100 58.21

TABLE 14 boiling temperature evaluation at the pressure of 1.013 barHCF₂OCF₂CF₂OCF₂H/n-hexane binary mixture COMPOSITION BOILING TEMPERATUREHCF₂OCF₂CF₂OCF₂H (% by wt.) (° C.) 0 68.00 20.6 56.24 39.7 48 81 59.946.74 73.8 46.66 78.7 46.76 89.9 49.00 100 58.21

TABLE 15 boiling temperature evaluation at the pressure of 1.013 barHCF₂OCF₂CF₂OCF₂H/tDCE binary mixture COMPOSITION BOILING TEMPERATUREHCF₂OCF₂CF₂OCF₂H (% by wt.) (° C.) 0 46.79 5.6 44.16 20.5 41.28 35.240.43 45.1 40.22 50.0 40.17 54.7 40.18 64.9 40.26 75.5 40.99 86.0 43.2295.0 49.37 100 58.21

TABLE 15 boiling temperature evaluation at the pressure of 1.013 barHCF₂OCF₂CF₂OCF₂H/tDCE binary mixture COMPOSITION BOILING TEMPERATUREHCF₂OCF₂CF₂OCF₂H (% by wt.) (° C.) 0 46.79 5.6 44.16 20.5 41.28 35.240.43 45.1 40.22 50.0 40.17 54.7 40.18 64.9 40.26 75.5 40.99 86.0 43.2295.0 49.37 100 58.21

TABLE 16 boiling temperature evaluation at the pressure of 1.013 barHCF₂OCF₂CF₂OCF₂H/ethyl alcohol binary mixture COMPOSITION BOILINGTEMPERATURE HCF₂OCF₂CF₂OCF₂H (% by wt.) (° C.) 0 78.50 20.6 72.35 48.963.70 62.6 60.12 80.0 57.33 89.7 56.07 94.7 55.65 98.0 55.75 99.0 56.02100 58.21

TABLE 16 boiling temperature evaluation at the pressure of 1.013 barHCF₂OCF₂CF₂OCF₂H/ethyl alcohol binary mixture COMPOSITION BOILINGTEMPERATURE HCF₂OCF₂CF₂OCF₂H (% by wt.) (° C.) 0 78.50 20.6 72.35 48.963.70 62.6 60.12 80.0 57.33 89.7 56.07 94.7 55.65 98.0 55.75 99.0 56.02100 58.21

TABLE 17 Azeotropic and near azeotropic behaviour evaluation bydetermination of the vapour pressure per cent variation afterevaporation of 50% of the initial liquid mass Binary mixtures ofdifluoromethoxy-bis (difluoromethyl e-ther)/1-difluoromethoxy-1,1,2,2-tetrafluoroethyl di- fluoromethyl etherInitial composi- tion HCF₂OCF₂OCF₂H/ HCF₂OCF₂CF₂OCF₂H TemperatureInitial pressure ΔP/P × 100 (% by wt.) (° C.) (bar) (%) 50.0/50.0 43.001.013 9.28  11.8/83.9* 53.97 1.013 6.71 60.3/39.7 41.57 1.013 5.92*contains 4.3% by weight of heavier impurities formed by HFPE having ahigher molecular weight

TABLE 17 Azeotropic and near azeotropic behaviour evaluation bydetermination of the vapour pressure per cent variation afterevaporation of 50% of the initial liquid mass Binary mixtures ofdifluoromethoxy-bis (difluoromethyl e-ther)/1-difluoromethoxy-1,1,2,2-tetrafluoroethyl di- fluoromethyl etherInitial composi- tion HCF₂OCF₂OCF₂H/ HCF₂OCF₂CF₂OCF₂H TemperatureInitial pressure ΔP/P × 100 (% by wt.) (° C.) (bar) (%) 50.0/50.0 43.001.013 9.28  11.8/83.9* 53.97 1.013 6.71 60.3/39.7 41.57 1.013 5.92*contains 4.3% by weight of heavier impurities formed by HFPE having ahigher molecular weight

EXAMPLE 2

The solvent effect of the HFPE-based mixtures is evaluated bydetermination of the Kauri-butanol index, reported in Table 19,according to ASTM D1133-86 method. The test has been however modified tolimit the losses due to the solvent evaporation with boiling temperaturelower than 40° C.; a 100 ml flask is used as vessel for theKauri-butanol solution; the end part of the buret containing the solventis inserted in a holed stopper closing the flask so as to carry out thetitration limiting the solvent evaporation. The Kauri-butanol solutionis stirred by a magnetic stirrer. The end titration point is identifiedin connection with a diffused turbidity which appears in theKauri-butanol solution due to the resin separation.

TABLE 19 Composition Solvent (% by wt.) Kauri-butanol index CFC 113(comp) 100 31 HFPE1/HFPE2/HCFC 123 14.5/9.5/76.0  33 Example compositionI HFPE1/HFPE2/n-pentane 12.0/49.0/39.0 25 Example compositions II, XHFPE1/HFPE2/n-hexane 14.8/59.0/26.2 26 Example compositions VII, XIIIHFPE1/HFPE2/tDCE  6.2/43.8/50.0 24 Example compositions IX, XIV HFPE1 =HCF₂OCF₂OCF₂H HFPE2 = HCF₂OCF₂CF₂OCF₂H

EXAMPLE 3

The oily product removal capacity from molded circuits has been verifiedaccording to the following method: a known amount of an oily product isuniformly spread on the molded circuit surface having 35×19 mm sizes;0.100 g of oil are spread on a single surface of the circuit, then thearticle is dipped in the solution to be tested.

After 5 minutes of dipping, the circuit is allowed to drie for further 5minutes at room temperature so as to remove the solvent traces and thenit is weighed again on an analytical balance.

The following oily products have been used:

1) Alkyl Benzene-Zerice S 46 oil by ESSO

2) FluoroSilicone-FS 1265 oil by DOW CORNIG

3) Ester-Icematic SW 100 oil by CASTROL

4) Mineral-Clavus 32 oil by SHELL.

Tests are carried out at room temperature (23-250° C.) and tests at theboiling temperature of the solvent mixtures. In the latter case thesolvent is placed in a vessel equipped with a refrigerant under refluxwhich recovers the vapour of the boiling solution.

In all the tests 30 ml of solvent solution have been used.

The results are reported in Table 20 expressed as removed oilpercentage.

TABLE 20 Percentage of removed oil for Temperature type of oil (% byweight) SOLVENT ° C. (1) (2) (3) (4) CFC 113 (comp) 23 100 99.5 100 100#  # # HFPE1/HFPE2/HCFC123 23 100 100 100 100 (14.5)(9.5)(76.0) # # # #Example composition I HFPE1/HFPE2/n-pentane 23 100 100 100 100(12.0)(49.0)(39.0) # # # # Example compositions II, XHFPE1/HFPE2/n-esano 23 100 100 100 100 (14.8)(59.0)(26.2) # # # #Example compositions VII, XIII HFPE1/HFPE2/methyl 51 88.1 100 100 81.0alcohol  # #  (18.8)(75.1)(6.1) Example composition XIIHFPE1/HFPE2/tDCE 25 100 100 100 100 (6.2)(43.8)(50.0) # # # # Examplecompositions IX, XIV HFPE1/HFPE2/acetone 66 100 100 100 100(15.9)(63.5)(20.6)  # #  Example compositions IV, XI HFPE1 =HCF₂OCF₂OCF₂H HFPE2 = HCF₂OCF₂CF₂OCF₂H 1) Alkyl Benzene-Zerice S 46 oilby ESSO 2) FluoroSilicone-FS 1265 oil by DOW CORNIG 3) Ester-Icematic SW100 oil by CASTROL 4) Mineral-Clavus 32 oil by SHELL.  The removed oilis not completely soluble in the solvent mixture at the test temperature# the oil removed is completely soluble in the solvent mixture at thetest temperature.

In many cases with the mixtures reported in Table 20 it is possible toobtain a wide solvent action towards oily products of different typewith results higher than or comparable with those offered by CFC 113.

Furthermore, the great availability of azeotropic and near azeotropicmixtures allows to select the best composition in connection with thetype of oily substance to be removed.

EXAMPLE 4

The HFC 134a and HFC 227 ea solubility with some solvent compositionsfor aerosol applications for the cleaning of electronic components isreported hereinafter.

TABLE 21 Propellant con- centration in admixture with Solvent com- thesolvent Temperature positions compositions (° C.) (% by wt.) Propellant(% by weight) 0 25 50 HFPE1/HFPE2/ HFC 134a 49.2 S S S n-hexane (14.8)(59.0) (26.2) HFPE1/HFPE2/ HFC 134a 48.8 S S S acetone (15.9) (63.5)(20.6) HFPE1/HFPE2/- HFC 134a 50.7 S S S methoxymethyl methylether(35.0) (24.0) (41.0) HFPE1/HFPE2/- HFC 227ea 38.1 S S S methoxymethylmethylether (35.0) (24.0) (41.0) HFPE1 = HCF₂OCF₂OCF₂H HFPE2 =HCF₂OCF₂CF₂OCF₂H S = The propellant is completely soluble in the usedsolvent.

EXAMPLE 5

The water removal from glass surfaces by means of some compositionsobject of the present invention is described.

In a cylindrical container having a 46 cm diameter and a 56 cm height,equipped with a neoprene closing stopper (cover), 30 ml of the solutionto be tested are introduced.

The compositions, indicated in Table 22, used for the water removaltests are prepared in a 50 ml flask and are heated in a thermostaticbath at a temperature of about 5° C. lower than the boiling temperatureof the solution itself.

The solutions are added of 600 ppm weight of a surfactant able to reducethe interfacial tension with water and favour the removal phenomenon ofthis from the surface subjected to drying; the tests have been carriedout in comparison with CFC 113 equivalently additioned of a surfactantconstituted by 1,1,2-dodecandiammonium-bis[di(3,6dioxapentadecyl)phosphate].

After heating the solution is transferred in the test container equippedwith cover.

On a glass surface having 37×25×1 mm sizes, 0.015 g of water aredeposited in the form of small drops.

The glass is placed on a metal frame which is used to carry out thearticle dipping in the liquid phase of the solution to be tested.

The container for the test is opened and the frame is slowly dipped intothe solution; the frame upper part runs in a hole made in the rubbercover (cap) which closes the container.

When two minutes have elapsed, the frame is lifted from the liquidphase, by letting run the external end part through the hole present inthe cover (cap); the glass will remain exposed to the solution vapoursfor one minute, then it is removed from the container and weighed.

In Table 22 the results relating to the water removal tests incomparison with the reference system formed by CFC 113, are reported.

The tested solutions allow to remove water in a similar way to thereference system.

TABLE 22 AGENT Temperature removed water solvent/drying (° C.) (% byweight) CFC 113* 42 100 HFPE1/HFPE2/HCFC123 23 100 (14.5) (9.5) (76.0))*HFPE1/HFPE2/tDCE 35 100 (6.2) (43.8) (50.0)* *contains 600 ppm by weightof 1,1,2-dodecandiammonium bis [di-(3,6 dioxapentadecyl)phosphate]

What is claimed is:
 1. Azeotropic or near azeotropic compositions, basedon difluoromethoxybis(difluoromethyl ether) and/or1-difluoromethoxy-1,1,2,2-tetrafluoroethyl difluoromethyl ether,selected from the group consisting of: composition % by weight I)difluoromethoxy  2-60 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);1,1-dichloro-2,2,2-trifluoroethane 98-40 (CHCl₂CF₃,HCFC 123 II)difluoromethoxy  1-95 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);n-pentane 99-5 III) difluoromethoxy  1-95 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); iso-pentane 99-1 IV) difluoromethoxy  1-60bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); dimethyl ketone (acetone)99-40 V) difluoromethoxy  1-99 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); 1,1,1,3,3-pentafluorobutane 99-1 (CF₃CH₂CF₂CH₃, HFC 365mfc) VI) difluoromethoxy  1-40 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); 1,1,1,4,4,4-hexafluorobutane 99-60 (CF₃CH₂CH₂CF₃, HFC356 ffa) VII) difluoromethoxy  1-96 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); methoxymethyl methylether 99-14 VIII) difluoromethoxy30-99 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); n-hexane 70-1 IX)difluoromethoxy  1-99 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); trans1,2-dichloroethylene 99-1 (ClCHCHCl, tDCE) X) 1-difluoromethoxy  1-931,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H);n-pentane 99-7 XI) 1-difluoromethoxy 30-99 1,1,2,2-tetrafluoroethyldifluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); dimethyl ketone (acetone) 70-1XII) 1-difluoromethoxy 50-99 1,1,2,2-tetrafluoroethyl difluoromethylether (HCF₂OCF₂CF₂OCF₂H); methyl alcohol 50-1 XIII) 1-difluoromethoxy15-99 1,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H);n-hexane 85-1 XIV) 1-difluoromethoxy  1-99 1,1,2,2-tetrafluoroethyldifluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); trans 1,2-dichloroethylene 99-1(ClCHCHCl) XV) 1-difluoromethoxy  5-99 1,1,2,2-tetrafluoroethyldifluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); ethyl alcohol 95-1 XVI)difluoromethoxy-  1-42 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);1,1-dichloro-2,2,2-trifluoroethane 98-24 (CHCl₂CF₃, HCFC 123)hydrocarbon  1-35 XVII) difluoromethoxy-  1-64 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); 1,1,1,3,3-pentafluorobutane 98-1 (CF₃CH₂CF₂CH₃, HFC 365mfc) hydrocarbon  1-35 XVIII) difluoromethoxy-  1-22 bis(difluoromethylether) (HCF₂OCF₂OCF₂H); 1,1,1,4,4,4-hexafluorobutane 98-43(Cf₃CH₂CH₂CF₃, HFC 356 ffa) hydrocarbon  1-35 XIX) difluoromethoxy- 1-55 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);1,1-dichloro-2,2,2-trifluoroethane 98-35 (CHCl₂CF₃, HCFC 123) alcohol 1-10 XX) difluoromethoxy-  1-89 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); 1,1,1,3,3-pentafluorobutane 98-1 (CF₃CH₂CF₂CH₃, HFC 365mfc) alcohol  1-10; and XXI) difluoromethoxy-  1-35 bis(difluoromethylether) (HCF₂OCF₂OCF₂H); 1,1,1,4,4,4-hexafluorobutane 98-55(Cf₃CH₂CH₂CF₃, HFC 356 ffa) alcohol  1-10.


2. Azeotropic or near azeotropic compositions according to claim 1,selected from the group consisting of: composition % by weight I)difluoromethoxy  2-54 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);1,1-dichloro-2,2,2-trifluoroethane 98-46 (CHCl₂CF₃, HCFC 123) II)difluoromethoxy 25-95 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);n-pentane 75-5 III) difluoromethoxy 25-98 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); iso-pentane 75-2 IV) difluoromethoxy 20-60bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); ketone (acetone) 80-40 V)difluoromethoxy 10-98 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);1,1,1,3,3-pentafluorobutane 90-2 (CF₃CH₂CF₂CH₃, HFC 365 mfc) VI)difluoromethoxy 10-40 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);1,1,1,4,4,4-hexafluorobutane 90-60 (CF₃CH₂CH₂CF₃, HFC 356 ffa) VII)difluoromethoxy 25-96 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);methoxymethyl methylether 75-14 VIII) difluoromethoxy 35-98bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); n-hexane 65-2 IX)difluoromethoxy 18-95 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); trans1,2-dichloroethylene 82-5 (ClCHCHCl, tDCE) X) 1-difluoromethoxy 25-931,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H);n-pentane 75-7 XI) 1-difluoromethoxy 50-98 1,1,2,2-tetrafluoroethyldifluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); diethel ketone (acetone) 50-2XII) 1-difluoromethoxy 60-98 1,1,2,2-tetrafluoroethyl difluoromethylether (HCF₂OCF₂CF₂OCF₂H); methyl alcohol 40-2 XIII) 1-difluoromethoxy25-98 1,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H);n-hexane 75-2 XIV) 1-difluoromethoxy 15-95 1,1,2,2-tetrafluoroethyldifluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); trans 1,2-dichloroethylene 85-5(ClCHCHCl); and XV) 1-difluoromethoxy 10-98 1,1,2,2-tetrafluoroethyldifluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); ethyl alcohol 90-2.


3. Azeotropic compositions according to claim 1 for which an absoluteminimum or maximum in the boiling temperature at the pressure of 1.013bar with respect to the pure products is exhibited and defined asfollows: A) difluoromethoxy- 24% by wt. bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); 1,1-dichloro-2,2,2-trifluoroethane 76% by wt.(CHCl₂CF₃, HCFC 123) B) difluoromethoxy- 62% by wt. bis(difluoromethylether) (HCF₂OCF₂OCF₂H); n-pentane 38% by wt. C) difluoromethoxy- 63% bywt. bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); iso-pentane 36% by wt. D)difluoromethoxy- 42% by wt. bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);dimethyl ketone (acetone) 58% by wt. E) difluoromethoxy- 60% by wt.bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); 1,1,1,3,3-pentafluorobutane40% by wt. (CF₃CH₂CF₂CH₃, HFC 365 mfc) F) difluoromethoxy- 20% by wt.bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); 1,1,1,4,4,4-hexafluorobutane80% by wt. (CF₃CH₂CH₂CF₃, HFC 356 ffa) G) difluoromethoxy- 59% by wt.bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); methoxymethyl methyl ether41% by wt. H) difluoromethoxy- bis(difluoromethyl ether) 75% by wt.(HCF₂OCF₂OCF₂H); n-hexane 25% by wt. I) difluoromethoxy- 75% by wt.bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); trans 1,2-dichloroethylene25% by wt. (ClCHCHCl, tDCE) 1-difluoromethoxy- 61% by wt.1,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H);n-pentane 39% by wt. M 1-difluoromethoxy- 79% by wt.1,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H);dimethyl ketone (acetone) 21% by wt. N) 1-difluoromethoxy- 94% by wt.1,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); methylalcohol  6% by wt. O) 1-difluoromethoxy- 74% by wt.1,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H);n-hexane 26% by wt. P) 1-difluoromethoxy- 50% by wt.1,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); trans1,2-dichloroethylene 50% by wt. (ClCHCHCl, tDCE); and Q)1-difluoromethoxy 95% by wt. 1,1,2,2-tetrafluoroethyl difluoromethylether (HCF₂OCF₂CF₂OCF₂H); ethyl alcohol  5% by wt.


4. Near azeotropic compositions according to claim 1, selected from thegroup consisting of: composition % by weight I) difluoromethoxy  2-60bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);1,1-dichloro-2,2,2-trifluoroethane 98-40 (CHCl₂CF₃, HCFC 123) III)difluoromethoxy  1-99 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);iso-pentane 99-1  IV) difluoromethoxy  1-60 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); dimethyl ketone (acetone) 99-40 V) difluoromethoxy 1-99 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);1,1,1,3,3-pentafluorobutane 99-1  (CF₃CH₂CF₂CH₃, HFC 365 mfc) VI)difluoromethoxy  1-40 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);1,1,1,4,4,4-hexafluorobutane 99-60 (CF₃CH₂CH₂CF₃, HFC 356 ffa); and VII)difluoromethoxy  1-96 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);methoxymethyl ether 99-14

wherein the difluoromethoxy-bis(difluoromethyl ether) part contains upto 40% by weight of1-difluoromethoxyl1,1,2,2-tetrafluoroethyldifluoromethyl ether.
 5. Nearazeotropic compositions according to claim 1, selected from the groupconsisting of: composition % by weight XI) 1-difluoromethoxy 30-991,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H);dimethyl ketone (acetone) 70-1  XII) 1-difluoromethoxy 50-991,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); methylalcohol   50-1; and XV) 1-difluoromethoxy  5-99 1,1,2,2-tetrafluoroethyldifluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); ethyl alcohol 95-1 

wherein 1-difluoromethoxy-1,1,2,2-tetrafluoroethyl difluoromethyl ethercontains up to 40% by weight of difluoromethoxy-bis(difluoromethylether).
 6. Near azeotropic compositions according to claim 1, selectedfrom the group consisting of: composition % by weight II)difluoromethoxy  1-95 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);n-pentane 99-5  VIII) difluoromethoxy 30-99 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); n-hexane   70-1; and IX) difluoromethoxy  1-99bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); trans 1,2-dichloroethylene99-1  (ClCHCHCl, tDCE)

wherein difluoromethoxy-bis(difluoromethyl ether) contains up to 50% of1-difluoromethoxy-1,1,2,2-tetrafluoroethyl difluoromethyl ether.
 7. Nearazeotropic compositions according to claim 1, selected from the groupconsisting of: composition % by weight X) 1-difluoromethoxy  1-931,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H);n-pentane 99-7  XIII) 1-difluoromethoxy 15-99 1,1,2,2-tetrafluoroethyldifluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); n-hexane   85-1; and XIV)1-difluoromethoxy  1-99 1,1,2,2-tetrafluoroethyl difluoromethyl ether(HCF₂OCF₂CF₂OCF₂H); trans 1,2-dichloroethylene 99-1  (ClCHCHCl)

wherein the 1-difluoromethoxy-1,2,2,2-tetrafluoroethyl difluoromethylether contains up to 50% by weight of difluoromethoxy-bis(difluoromethylether).
 8. Near azeotropic compositions according to claim 1, based ondifluoromethoxy-bis(difluoromethyl ether) and hydrocarbons selected fromthe group consisting of: composition % by weight XVI) difluoromethoxy- 1-42 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);1,1-dichloro-2,2,2-trifluoroethane 98-24 (CHCl₂CF₃, HCFC 123)hydrocarbon  1-35 XVII) difluoromethoxy-  1-64 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); 1,1,1,3,3-pentafluorobutane 98-1  (CF₃CH₂CF₂CH₃, HFC365 mfc) hydrocarbon    1-35; and XVIII) difluoromethoxy-  1-22bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); 1,1,1,4,4,4-hexafluorobutane98-43 (CF₃CH₂CH₂CF₃, HFC 356 ffa) hydrocarbon    1-35. --


9. Compositions according to claim 8, wherein hydrocarbon is selectedbetween n-pentane and iso-pentane.
 10. Compositions according to claim8, wherein hydrocarbon is present in the range 1-20% by weight.
 11. Nearazeotropic compositions according to claim 1, based ondifluoromethoxy-bis(difluoromethyl ether) and alcohol selected from thegroup essentially consisting of: composition % by weight XIX)difluoromethoxy-  1-55 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);1,1-dichloro-2,2,2-trifluoroethane 98-35 (CHCl₂CF₃, HCFC 123) alcohol 1-10 XX) difluoromethoxy-  1-89 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); 1,1,1,3,3-pentafluorobutane 98-1  (CF₃CH₂CF₂CH₃, HFC365 mfc) alcohol    1-10; and XXI) difluoromethoxy-  1-35bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); 1,1,1,4,4,4-hexafluorobutane98-55 (CF₃CH₂CH₂CF₃, HFC 356 ffa) alcohol    1-10. --


12. Compositions according to claim 11, wherein alcohol is methylalcohol.
 13. Compositions according to claim 11, wherein alcohol ispresent between 1 and 5% by weight.
 14. Azeotropic or near azeotropiccompositions according to claim 1, wherein the ether part can contain atleast up to 10% by weight of hydrofluoro ethers having same structurehaving a boiling point in the range 5-80° C.
 15. A method for removingcontaminants from surfaces wherein said surfaces are contacted withsubstitutes for CFC 113, comprising azeotropic and near azeotropiccompositions selected from the group consisting of: composition % byweight I) difluoromethoxy  2-60 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); 1,1-dichloro-2,2,2-trifluoroethane 98-40 (CHCl₂CF₃,HCFC 123) II) difluoromethoxy  1-95 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); n-pentane 95-5 III) difluoromethoxy  1-99bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); iso-pentane 99-1 IV)difluoromethoxy  1-60 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);dimethyl ketone (acetone) 99-40 V) difluoromethoxy  1-99bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); 1,1,1,3,3-pentafluorobutane99-1 (CF₃CH₂CF₂CH₃, HFC 365 mfc) VI) difluoromethoxy  1-40bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); 1,1,1,4,4,4-hexafluorobutane99-60 (CF₃CH₂CF₂CF₃, HFC 356 ffa) VII) difluoromethoxy  1-96bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); methoxymethyl methylether99-14 VIII) difluoromethoxy 30-99 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); n-hexane 70-1 IX) difluoromethoxy  1-99bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H); trans 1,2-dichloroethylene99-1 (ClCHCHCl, tDCE) X) 1-difluoromethoxy  1-931,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H);n-pentane 99-7 XI) 1-difluoromethoxy 30-99 1,1,2,2-tetrafluoroethyldifluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); dimethyl ketone (acetone) 70-1XII) 1-difluoromethoxy 50-99 1,1,2,2-tetrafluoroethyl difluoromethylether (HCF₂OCF₂CF₂OCF₂H); methyl alcohol 50-1 XIII) 1-difluoromethoxy15-99 1,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF₂OCF₂CF₂OCF₂H);n-hexane 85-1 XIV) 1-difluoromethoxy  1-99 1,1,2,2-tetrafluoroethyldifluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); trans 1,2-dichloroethylene 99-1(ClCHCHCl) XV) 1-difluoromethoxy  5-99 1,1,2,2-tetrafluoroethyldifluoromethyl ether (HCF₂OCF₂CF₂OCF₂H); ethyl alcohol 95-1 XVI)difluoromethoxy-  1-42 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);1,1-dichloro-2,2,2-trifluoroethane 98-1 (CHCl₂CF₃, HFC 123) hydrocarbon 1-35 XVII) difluoromethoxy-  1-64 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); 1,1,1,3,3-pentafluorobutane 98-1 (CF₃CH₂CF₂CH₃, HFC 365mfc) hydrocarbon  1-35 XVIII) difluoromethoxy-  1-22 bis(difluoromethylether) (HCF₂OCF₂OCF₂H); 1,1,1,4,4,4-hexafluorobutane 98-43(CF₃CH₂CH₂CF₃, HFC 356 ffa) hydrocarbon  1-35 XIX) difluoromethoxy- 1-55 bis(difluoromethyl ether) (HCF₂OCF₂OCF₂H);1,1-dichloro-2,2,2-trifluoroethane 98-35 (CHCl₂CF₃, HFC 123) alcohol 1-10 XX) difluoromethoxy-  1-89 bis(difluoromethyl ether)(HCF₂OCF₂OCF₂H); 1,1,1,3,3-pentafluorobutane 98-1 (CF₃CH₂CF₂CH₃, HFC 365mfc) alcohol  1-10; and XXI) difluoromethoxy-  1-35 bis(difluoromethylether) (HCF₂OCF₂OCF₂H); 1,1,1,4,4,4-hexafluorobutane 98-55(CF₃CH₂CH₂CF₃, HFC 356 ffa) alcohol  1-10.


16. The method according to claim 15, wherein the compositions furthercomprise one or more non-ionic surfactants wherein the concentration ofsaid one or more surfactants is in the range 0.005-5% by weight based onthe azeotropic or near azeotropic components.
 17. The method accordingto claim 15, wherein the composition further comprises solvent/dryingagents.
 18. The method according to claim 17, wherein stabilizers forradicalic decomposition reactions are added to the composition inconcentrations in the range 0.1-5% by weight with respect to thesolvent-detergent and/or drying agent.
 19. The method according to claim15, wherein the compositions are combined with one or more propellantsfor the cleaning electronic components.
 20. The method according toclaim 19, wherein the propellant is selected from: HFC 134a(1,1,1,2-tetrafluoroethane), HFC 227ea(1,1,1,2,3,3,3-heptafluoropropane) or mixtures thereof.